02-clone-image-on-ssd.md

Clone SD image on SSD disk and mount it as root

NOTE: after a long research, and many trial and error attempts, I could not make the system to boot entirely from SSD, but only mounting the root partition. Thus, at the moment, the following guide allows you to boot from SD and mount root from SSD right after boot. It could be possible to make it work by using the vcgencmd command to set the BOOT_ORDER=0xf41 parameter as explained in the official Raspberry Pi guide. At the time of writing this, Debian for raspberry does not have the vcgencmd in its repository, and I had not yet time to workaround on this.

0. Hardware setup

We assume that all Raspberry Pis are up, and running the new Debian image from the SD.

1. Connect SSD to USB.

Each SSD should be attached to its RPi through the USB to SATA adapter.

NOTE: If you haven't used the install-sd.sh script, you'll have to manually download rpi-clone repo, as follows. Otherwise, you can skip the next 3 steps and continue from the 5th step onwards.

NOTE: There's a script (scripts/clone-root-to-ssd.sh) which covers these steps as well, but my recommendation is to first gain confidence with the following commands by running them manually a couple of times.

2. On host download rpi-clone compressed directory from official GitHub repo.

3. Unzip it:

unzip master.zip

4. and SCP it into the root home on RPis:

scp -r rpi-clone-master root@<RPi-address>

5. Now connect to the Raspberry Pis and execute the base checks:

lsblk

Ouptut:

NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda           8:0    0 931.5G  0 disk
mmcblk1     179:0    0  14.8G  0 disk 
|-mmcblk1p1 179:1    0   299M  0 part /boot/firmware
`-mmcblk1p2 179:2    0  14.5G  0 part /

in this case /dev/sda is the target disk.

6. Prepare configuration files before the clone:

• replace root=LABEL=RASPIROOT with root=LABEL=ROOT in the /boot/firmware/cmdline.txt file;
• replace LABEL=RASPIROOT with LABEL=ROOT in the /etc/fstab file;
• replace ROOTPART=LABEL=RASPIROOT with ROOTPART=LABEL=ROOT in the /etc/default/raspi-firmware file.

Since we are touching the cmdline.txt file, we should as well set the cgroups required for running containers:

console=tty0 console=ttyS1,115200 root=LABEL=ROOT rootfstype=ext4 fsck.repair=yes rootwait elevator=deadline cgroup_memory=1 cgroup_enable=memory cgroup_enable=cpuset

Let's add the extra file to persist the changes:

cat <<EOS > /etc/default/raspi-extra-cmdline
elevator=deadline cgroup_memory=1 cgroup_enable=memory cgroup_enable=cpuset
EOS

7. Perform apt update before running rpi-clone.

apt update

8. Preparing SSD

There are many ways we can use the SSD to expose the storage as persistent volume in Kubernetes. My recommendation at this stage is to dedicate the first two partitions to boot and root respectively, and to use the remaining disk space as Kubernetes storage.

Before cloning the data with the rpi-clone script, the SSD should present the same partition table. To copy the partition table we will use sfdisk to dump it as follows:

sfdisk -d /dev/mmcblk1 > partition_table_sd

Then we write the table to the SSD:

sfdisk /dev/sda < partition_table_sd

This allows rpi-clone script to automatically perform the right actions for cloning the SD data to the SDD (see point 7 of the README).

First, let's increase the size of the root partition on the SSD, using cfdisk, e.g. increase it to 32 or 64 GB:

cfdisk /dev/sda

Then recreate the filsystem with the right label:

mkfs.ext4 /dev/sda2 -L ROOT

9. Cloning SD to SSD

Run the rpi-clone script:

./rpi-clone-master/rpi-clone /dev/sda

Output if some packages are missing:

Command not found: rsync       Package required: rsync
Command not found: column      Package required: bsdmainutils

Do you want to apt-get install the packages?  (yes/no): yes

Answer yes and proceed.

Then:

Booted disk: mmcblk1 15.9GB                Destination disk: sda 1.0TB
---------------------------------------------------------------------------
Part               Size    FS     Label           Part   Size    FS     Label
1 /boot/firmware   508.0M  fat16  --              1      508.0M  fat16  --
2 root              14.3G  ext4   RASPIROOT       2       64.0G  ext4   ROOT
---------------------------------------------------------------------------
== SYNC mmcblk1 file systems to sda ==
/boot/firmware        (82.0M used)   : SYNC to sda1 (508.0M size)
/                     (928.0M used)  : SYNC to sda2 (64.0G size)
---------------------------------------------------------------------------
Run setup script       : no.
Verbose mode           : no.
-----------------------:

Ok to proceed with the clone?  (yes/no): yes

Enter yes to proceed:

Syncing file systems (can take a long time)
Syncing mounted partitions:
  Mounting /dev/sda2 on /mnt/clone
mount: (hint) your fstab has been modified, but systemd still uses
       the old version; use 'systemctl daemon-reload' to reload.
  => rsync // /mnt/clone with-root-excludes ...
  Mounting /dev/sda1 on /mnt/clone/boot/firmware
mount: (hint) your fstab has been modified, but systemd still uses
       the old version; use 'systemctl daemon-reload' to reload.
  => rsync /boot/firmware/ /mnt/clone/boot/firmware  ...

===============================
Done with clone to /dev/sda
   Start - 22:36:18    End - 22:36:29    Elapsed Time - 0:11

Cloned partitions are mounted on /mnt/clone for inspection or customizing.

Hit Enter when ready to unmount the /dev/sda partitions ...
  unmounting /mnt/clone/boot/firmware
  unmounting /mnt/clone
===============================

10. Reboot the RPi system to check whether the changes will be successfully applied:

systemctl reboot

11. Reconnect and verify:

lsblk

Output:

NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
sda           8:0    0 931.5G  0 disk
|-sda1        8:1    0   508M  0 part
`-sda2        8:2    0    64G  0 part /
mmcblk1     179:0    0  14.8G  0 disk
|-mmcblk1p1 179:1    0   508M  0 part /boot/firmware
`-mmcblk1p2 179:2    0  14.3G  0 part